DESCRIPTION: Neovascularization is associated with two ocular disorders, macular degeneration and diabetic retinopathy. Both conditions are high profile disorders that have significant association with visual impairments and blindness. Presently, there are only preventative measures taken by clinicians to slow the progression of the diseases. No curative therapies have been found despite intensive research. Later photocoagulation is the current methodology for the treatment of neovascularization in the eye. However, normal tissues and vessels adjacent to the targeted site are irreversibly damaged by lateral transfer of heat. The ideal therapeutic modality would provide for highly selective and finely controlled destruction of the involved blood vessels and/or area while minimizing damage to adjacent normal tissues. it is the aim of this project to expand preliminary investigations on the use of photodynamic therapy (PDT) using tin ethyl etiopurpurin (SnET2) for the treatment of neovascularization in the eye. PDT holds promise as a more efficacious treatment modality than thermal photocoagulation due to its low energy, non thermal light activation of a photosensitizer leading to localized selective vessel destruction, thus sparing normal tissues. If the data resulting from Phase I studies looks efficacious, further preclinical development can be pursued in Phase II to determine optimum combinations of photosensitizer and light doses for maximum therapeutic benefit.